Location of the subwoofer

hbrandi

Hello again!

One friend is telling me that the preffered location for an optimal sound flow would be from the front to the back. I was courious because I have seen a lot of installations that the subwoofer is located on the back of the car. But I also know that the Jeep has a front subwoofer. What would be the best location for a subwoofer?

Regards.

MacLeod

The reason youd put a sub in front is ideally you want all music coming from in front of you and having bass coming from the back while everything else is coming from the front messes up your soundstage.

That being said its not that hard to use a sub in the rear and have it blend with the front.

One way in say a hatchback or SUV is to mount it in a corner. I have my MTX downfiring under the rear passenger seat and you couldnt locate the bass if you tried!

Also crossing over the bass lower will usually pull the bass up front as well. If your sub is putting out 100 Hz and down it becomes pretty apparant where its coming from. Whereas a sub hitting 70 Hz and below (which is where mine is crossed over) does little more than add punch and is very difficult to locate.

All this tho is worthless if your front stage is incapable of decent midbass.

neomagus00

minor translation: putting a subwoofer in the trunk is no problem, because locating the source of very low frequencies is exceedingly difficult for the human ear. ideally, yes, you would want your sub up front, because then any distortion (and every sub has it) is also up front. however, with a decent sub and decent front speakers, the distortion effect is so minor that it is ridiculously difficult to locate where the sub is placed. so, it's no big deal to stick it in the trunk. as mac said, if you allow the front speakers to play lower, and cross the sub over lower as well, it becomes even more difficult to locate the bass. and, yay for psychoacoustics, since your mind can't tell where the sub-bass is coming from, it assumes it's coming from where the rest of the sound is - namely the front of the car.

i believe the reason the jeep would have a sub in front is because there's no other place to put it...

MacLeod

Yeah, the Jeep has it in the center console. I really dont like it there because it doesnt seem to blend well with the front stage. However Ive only heard this configuration in 1 Dodge Ram. The guy had a 12W6 fab'd under his center. It hit hard and sounded good but made the stage funky.

I recently went back to my MTX 8 because I was tired of the JL's taking up my back seat and stumbled onto something. Previously I had it crossed at 80 Hz and it wasnt that hard to locate it coming from the corner. The JL's were also crossed at 80 and they too could easily be found right behind me. When I put the MTX back in I decided to cross it over a little lower cause I was giving it 2.5 times its rated power and thought Id spare it a little work so I crossed it at 70 Hz. Now it may be my imagination but the sub is now virtually invisible. I wouldnt think 10 Hz could make a difference but maybe with the accoustics and layout of my truck 70 was the magic number!

neomagus00

if you consider that 10 Hz to be 15% of the entire sub-bass realm, it makes more sense...

MacLeod

Yeah, never thought of it that way.

Makes me wonder what else Im missing out on by not fine tuning my system a little more. Ah, Ill wait til I get me some components. Cant really fine tune 6x9s! LOL

neomagus00

yeah, that does kinda make you wonder... i've been learning this bit by bit by playing with my equalizer... it's quite impressive what a 1 dB boost or cut can do to the sound, especially with voice, and especially with female voices.

MacLeod

I need an EQ. Gonna be a **** to find a place to install it tho.

neomagus00

hmm... there's the in-dash ones, but they're at most 13-band graphical eq's... the biggest parametric i've seen in-dash is 5+1 bands... i've seen 31-banders mounted vertically between seats and the console, so that they came up and over your lap like a folding-top desk... i dunno other than that, where it would be easy to access so you can listen and tune at the same time...

MacLeod

OK. I know dick about EQ's. I know parametric is supposed to be better than graphic and all but what the hell does that mean?

exalted512

what ive seen most ppl do is put it to where they think a good place for it will be...when i get one ill probably get some type of metal stand and raise it right over my XM tuner under the seat
but theyll leave it unscrewed for a few months or until everything is set, then screw it in...then if you really need to make adjustments just take it out or whatever
-Cody

neomagus00

okey... i'll start from the beginning, just so we're on the same page. an equalizer adjusts different bands of frequencies, up and down, within a certain limit; i'm sure you already knew that. they do it in different ways, and each has its pros and cons, but really, in a car, it is extraordinarily difficult to tell the differences amongst these different types, so we'll ignore them. each eq has a number of bands. most eq's have their bands completely defined. before i explain what that means, let's make sure we know that the shape of the curve is unusual.

say we're feeding a perfectly flat source into the equalizer. then, if there's no equalization going on, no matter what frequency you measure, they're all the same - a perfectly flat response. good. now let's screw it up - let's put in 3 dB of boost on to say 500 Hz cause we like it like that. the response curve is no longer going to be a straight line. it will approach 500 Hz, and as it gets closer, it will begin to rise, steeper and steeper, till it gets to 500 Hz; then it will very quickly turn over and fall back to reference level, leveling out as it gets further down. it's a quartic function, approximately, if you're familiar.

so we know that it's a specific shape. a standard eq makes that center frequency (500 in our example) and the width, or "Q", of the curve, set. you can't change either. with a true parametric equalizer, you can set the center frequency to whatever you want, and you can change the width of the curve to a very wide range of values (usually from around 2 octaves down to around .02 octaves). so, if you have a very sharp spike at 344 Hz for some reason, a parametric eq will allow you to dial in 344 Hz for the center frequency and a high q (narrow curve), so that you can eliminate that spike without touching the rest of the frequencies.

i should note that a cool type of equalizer is the true graphic equalizer. for most eq's, if you take two adjacent bands and dial in +3 dB boost, the frequencies in between will drop slightly - you won't get +3 in between the two centers of the 2 bands. a true graphic equalizer is almost always calibrated using sliders, as opposed to dials, and it fixes that problem. if you dial in +3 dB on two adjacent bands, the true graphic eq will make it such that every frequency in between is also +3 dB. two notes on this: first, i'm calling it a true graphic eq because some people will label a digital eq as 'graphic' - hey, it's got pictures! - but this is not accurate. this is because (note 2: ) it's called graphic because if you use a panel of sliders, the curve drawn out by the centers of the sliders (low frequency at the left, high right) is exactly the equalization curve you're putting on the sound. a non-graphic eq with sliders will not look exactly like the curve you're putting on the source.

any questions?

MacLeod

So the main difference between a parametric and graphic EQ is that while both allow you to adjust a certain frequency, the parametric allows you to adjust the slope?

Kind of like the difference between the slopes of a 12 db x-over and a 24 db x-over.'

I gotcha. Youre pretty smart for a hippy!

AustinKP

Originally posted by MacLeod
So the main difference between a parametric and graphic EQ is that while both allow you to adjust a certain frequency, the parametric allows you to adjust the slope?

Kind of like the difference between the slopes of a 12 db x-over and a 24 db x-over.'

Well, not only the slope, but also the center of the slope. A graphic equalizer has its center points defined. A parametric equalizer allows you to move each peak left or right(lower or higher freqs) as well as the amplitude and slope.

So while a graphic equalizer might have sliders at 100 and 500 Hz, a parametric would allow you to move the peak anywhere in-between, in case you happen to want to have your peak at 274Hz. More accurate equalization is possible this way.

MacLeod

Ah, ok. Got it now.

neomagus00

cool if you're a more visual guy, jl has a decent enough picture of the idea : http://www.jlaudio.com/tutorials/index.html, first one.